A laboratory study on sand grain impacts and their role in releasing fine dust into the Martian atmosphere
- University of Duisburg-Essen, Physics, Duisburg, Germany
Dust in the Martian atmosphere is (under regular conditions) not larger than a few micrometers in diameter.
Liberation through impacts of sand grains during saltation is thought to be one source of this fine dust within
the atmosphere, as windspeeds usually do not exceed the threshold windspeed needed to pick up the highly
adhesive smallest particles directly.
We conducted a laboratory experiment to take a closer look at these saltating impacts and the resulting PSD of
the Ejecta on a microscopic scale: A small number of particles of about 200μm in diameter impacted a
simulated Martian soil (bimodal Mars Global Simulant). Impacts occurred at flat angles in fine vacuum
(10-2 mbar) with an impact speed of ∼ 1 m/s. The ejected dust was captured on adjacent
microscope slides and its size distribution was analyzed.
We find that the probability for ejection decreases dramatically with decreasing size. However, in spite of
strong adhesive forces, individual impacts still emit dust of 1μm and less. In fact, the probability
of ejecting dust of a given size can be characterized by a power law in the decade between 0.5μm
and 5μm (diameter).
How to cite: Becker, T., Wurm, G., and Teiser, J.: A laboratory study on sand grain impacts and their role in releasing fine dust into the Martian atmosphere, Europlanet Science Congress 2022, Granada, Spain, 18–23 Sep 2022, EPSC2022-13, https://doi.org/10.5194/epsc2022-13, 2022.
